Besides htmldoc is there any other way to convert all html documents in a folder recursively to pdf files?
I've used something called wkhtmltopdf with much success. http://code.google.com/p/wkhtmltopdf/ or just apt-get install wkhtmltopdf .
Usage is on the command line with like wkhtmltopdf <path-to-html-file-or-url> output.pdf , and many parameters you can tweak for quality, size, etc. Of course, its easy to now put this in a bash script to loop over all html files in a folder, etc.
This tool uses the webkit rendering engine to render the html page, and then converts this snapshot to a pdf. In my experience, it has rendered to pdf flawlessly even quite complicated page layouts, which other html to pdf converters seem not to do. Basically, if a page looks fine in a webkit based browser, its likely output the pdf exactly the way it looks as a webpage.
I think the version in the repositories requires the machine to have X installed, but if you install the newest version from the google code page, it can run on a server without X installed.
Best of luck, Sanjay